Advertisements
Advertisements
प्रश्न
A cricket ball of mass 150 g has an initial velocity `u = (3hati + 4hatj)` m s−1 and a final velocity `v = - (3hati + 4hatj)` m s−1 after being hit. The change in momentum (final momentum-initial momentum) is (in kg m s1)
विकल्प
zero
`-(0.45 hati + 0.6 hatj)`
`-(0.9 hati + 1.2 hatj)`
`-5 (hati + hatj)`
Advertisements
उत्तर
`-(0.9 hati + 1.2 hatj)`
Explanation:
Given, `u = (3hati + 4hatj)` m/s
And `v = - (3hati + 4hatj)` m/s
Mass of the ball = 150 g = 0.15 kg
Δp = Change in momentum
= Final momentum – Initial momentum
= `mv - mu`
= `m(v - u) = (0.15) [- (3hati + 4hatj) - (3hati + 4hatj)]`
= `(0.15) xx [ - 6hati - 8hatj]`
= `- [0.15 xx 6hati + 0.15 xx 8hatj]`
= `- [0.9 hati + 1.20 hatj]`
Hence, Δp = `-[0.9 hati + 1.2 hatj]`
APPEARS IN
संबंधित प्रश्न
A person says that he measured the acceleration of a particle to be non-zero even though no force was acting on the particle.
A block of mass 0.2 kg is suspended from the ceiling by a light string. A second block of mass 0.3 kg is suspended from the first block by another string. Find the tensions in the two strings. Take g = 10 m/s2.
Two blocks of equal mass m are tied to each other through a light string. One of the blocks is pulled along the line joining them with a constant force F. Find the tension in the string joining the blocks.
A particle of mass 0.3 kg is subjected to a force F = −kx with k = 15 N/m. What will be its initial acceleration if it is released from a point x = 20 cm?
A small block B is placed on another block A of mass 5 kg and length 20 cm. Initially, the block B is near the right end of block A (In the following Figure). A constant horizontal force of 10 N is applied to the block A. All the surfaces are assumed frictionless. Find the time that elapses before block B separates from A.
A man has fallen into a ditch of width d and two of his friends are slowly pulling him out using a light rope and two fixed pulleys as shown in the following figure. Show that the force (assumed equal for both the friends) exerted by each friend on the road increases as the man moves up. Find the force when the man is at a depth h.
Find the acceleration of the blocks A and B in the three situations shown in the following figure.
In the following figure shows a man of mass 60 kg standing on a light weighing machine kept in a box of mass 30 kg. The box is hanging from a pulley fixed to the ceiling by a light rope, the other end of which is held by the man himself. If the man manages to keep the box at rest, what is the weight recorded on the machine? What force should he exert on the rope to record his correct weight on the machine?
A tennis ball and a cricket ball , both are stationary. To start motion in them .
Show that the rate of change of momentum = mass × acceleration. Under what condition does this relation hold?
Two bodies A and B of same mass are moving with velocities v and 2v, respectively. Compare their (i) inertia and (ii) momentum.
State Newton's second law of motion. Under what condition does it take the form F = ma?
Use Newton's second law of motion to explain the following instance :
An athlete prefers to land on sand instead of hard floor while taking a high jump .
State the magnitude and direction of the force of gravity acting on the body of mass 5 kg. Take g = 9.8 m s-2.
A stone is dropped freely from the top of a tower and it reaches the ground in 4 s. Taking g = 10m s-2, calculate the height of the tower.
A body of mass 200 g is moving with a velocity of 5 ms−1. If the velocity of the body changes to 17 ms−1, calculate the change in linear momentum of the body.
What do you understand by the term momentum?
Use Newton's second law to explain the following:
While catching a fast moving ball, we always pull our hands backwards.
A body of mass 2 kg travels according to the law x(t) = pt + qt2 + rt3 where p = 3 ms−1, q = 4 ms−2 and r = 5 ms−3. The force acting on the body at t = 2 seconds is ______.
